This invention relates to improvements in endless printing ribbon cartridges for use in high speed band printers. Recent years have seen the development of such high speed printers, for example, of the type used in connection with computer systems or the like. It is among the desirable characteristics of such printers that there be a simple, trouble-free ribbon cartridge by which a substantially continuous supply of printing ribbon can be loaded in and fed through the printer.
It often is desirable to include a device for inverting the ribbon each time it passes through the cartridge so as to present the opposite face of the ribbon to the paper with each pass of the ribbon. For example, in my prior joint application Ser. No. 897,861 filed Apr. 19, 1978, now abandoned in favor of continuing application Ser. No. 67,770 filed Aug. 20, 1979, now U.S. Pat. No. 4,293,234 issued Oct. 6, 1981 to Edward H. Yonkers and Gilbert A. LeDonx, a mobius loop structure is incorporated in the cartridge adjacent the outlet end of the cartridge to reverse the surfaces of the ribbon. The present invention relates to further improvements in the ribbon inverting means as well as further improvements in the general construction of the cartridge by which it may be fabricated at less expense without sacrificing reliability of operation.
In brief, the cartridge includes an elongate housing which may be formed from a pair of mateable top and bottom sections which may be molded from plastic. The cartridge has an inlet and outlet end through which the printing ribbon enters and exits. A pair of arms extend from the inlet and outlet ends of the housing to define a generally U-shaped configuration, and serve to guide the ribbon into and then out of the housing. The main body of the cartridge, in-between the arms, defines a ribbon storage compartment where the ribbon is contained in a multiplicity of serpentine folds. Openings are provided in the bottom wall of the cartridge, between the inlet arm and storage chamber, to receive the drive rolls of the printer. They grip a portion of the ribbon and advance the ribbon continuously through the device.
The top and bottom members of the cartridge are formed, near the outlet end of the cartridge, to define a plurality of projections which extend internally into the cartridge and which define a plurality of ridge surfaces spaced along the path of ribbon travel which engage the ribbon and reverse it as the ribbon progresses sequentially through the series of ridges. The projections and ribbon-engaging ridges are molded directly from and are integral with the top and bottom members of the cartridge thus avoiding the necessity of fabricating and assembling more complicated types of ribbon-inverting devices. In addition, the construction of the cartridge and the manner in which the ribbon inverting ridges are formed facilitates assembly of the device as well as providing other advantages described herein.
It is among the general object of the invention to provide a ribbon cartridge for a high speed band printer having an improved, simplified and inexpensive construction.
Another object of the invention is to provide a ribbon cartridge of the type described having a ribbon-inverting means adjacent its outlet end which is formed integrally with the cartridge body.
A further object of the invention is to provide a ribbon cartridge of the type described in which the ribbon-inverting means is in the form of a series of ribbon-engaging ridges formed integrally with the cartridge and which project internally of the cartridge to engage the ribbon and guide it into an inverted configuration.
Another object of the invention is to provide a ribbon cartridge of the type described in which the ribbon-inverting means imposes minimal wear on the ribbon.
A further object of the invention is to provide a ribbon cartridge of the type described having a ribbon-inverting means which reduces assembly procedures and which results in a low cost device without sacrificing reliability of operation.
Still another object of the invention is to provide a ribbon cartridge which is low cost and of inexpensive construction and which embodies simple mechanisms whereby the device lends itself to disposable use.